Process for burning size from glass fabric and coating the resulting fabric



July 29, 1958 J. H. WAGGONER 2,845,354

PROCESS'FOR BURNING SIZE FROM GLASS FABRIC 7 AND COATING THE RESULTING FABRIC Filed March 1, 1954 2 Sheets-Sheet 1 INVENTOR. o 40% gym ATTORNEYS.

Juls' 29,

J. H. WAGGON ER 2,845,364

PROCESS FOR BURNING SIZE FROM GLASS FABRIC AND' COATING THE RESULTING FABRIC 2 Sheets-Sheet 2 Filed March 1, 1954 h f hw INVENTOR.

ATTORNEYS- 2,845,364 PROCESS FOR BURNING SIZE FROM GLASS FABRIC AND COATING THE RESULTING FABRIC Jack H. Waggoner, Newark, Ohio, assignor to Owens-Corning Fiberglas Corporation, a corporation of Delaware Application March 1, 1954, Serial No. 413,344

' p 4 Claims. (Cl. 117-46) This invention relates to the manufacture of textile fabrics of glass fibers. This application is a continuationin-part of application Ser. No. 91,841, filed May 6, 1949, now abandoned.

'-It is an object of this invention to produce and to provide a method for producing glass fiber fabrics having some of the qualities of the finest silks, satins and woolens; which when used as a hanging or a curtain or the like, drape very readily into soft and rippling folds; and which have good hand'and feel. It is an object of this invention to secure these characteristics, novel to glass fiber fabrics, without undue sacrifice of strength or fireproofness, or without diminishing resistance to heat, rot, vermin, weather, moisture and the like, properties which make glass fibers ideally suited as a textile material, fibrous reinforcement, and for many other purposes. Fabrics of glass fibers have additional merit in that glass fibers are shrinkproof and are not easily soiled, those that are soiled are readily cleansed by a light aqueous rinse.

'Another object is to produce a glass fiber fabric which is substantially wrinkle and crease resistant and is characterized by its ability quickly to return to its original condition without requiring the usual stretching or ironing operations normally employed in the textile trade.

A further object is to produce a glass fiber fabric in which the fibers are relaxed to the extent that free ends, including those resulting from fiber breakage, do not stand out from the face of the fabric as frayed or loose ends to detract from the appearance of the fabric. Instead the ends lie in their normal position in the fabric so that breakage or loose ends are not evident.

A still further object is to produce a glass fiber fabric which, depending upon modifications in fabricating steps, may be varied from silky softness to starchy stiffness, which properties remain as permanent characteristics of the fabric.

A still further object is to produce a glass fiber fabric having predetermined designs in relief or intaglio, permanently formed in the fabric during the fabrication steps without influence or impairment of the other characteristics of the textile heretofore described.

Another object is to produce and to provide a method for producing a textile fabric of glass fibers wherein the fibers are crimped or curly throughout their lengths to increase the ability of the fibers to cling together, and it is a related object to produce crimped or curly fibers arranged as substantially individual staple fibers having some of the felting characteristics and the appearance of wool and that may be carded or otherwise fabricated into a textile.

A still further object is to provide a colored textile fabric of glass fibers having many of the characteristics previously described.

It is a further object to provide a glass fiber fabric that has markedly improved resistance to unraveling or fraying at out edges and that has increased strength at the seams and hem's and along other lines where two or more fabric pieces are stitched together.

It is still another object of the invention to produce a supple textile fabric of glass fibers which has excellent appearance, permanent dimension, and which may be ice fabricated to have the characteristics heretofore described by a novel and economical mass production method, and which may constitute a base for coated fabrics or a reinforcement in plastics and laminates. I

These and other characteristics desirable in a glass fiber fabric are achieved by our process wherein the glass fibers in fabric form are subjected to successive thermal treatments, the first of which, hereinafter referred to as weave setting, functions chiefly to relax the fibers in the positions normally taken in the woven fabric, and to set the weave. The second thermal reaction is carried out with an organo silicon compound on the surfaces of the fibers to form what is believed to be a reaction product that contributes immensely to the attainment of the new and novel characteristics in a glass fiber fabric. The latter heat treatment will hereinafter be referred to as the heat curing step.

Weave setting is carried out at a temperature above 900 F. but below the fiber fusing temperature, which temperature depends primarily on the particular glass composition. It is safest to set the maximum temperature at about 50l0() F. below the fusion temperature for the particular glass composition of which the fibers are formed. For example, the preferred weave setting range for glass fibers of borosilicate glass is between 1000 F., but usually below 1300 F. Within the temperature range,

' fiber relaxation and weave setting of a desirable character is secured upon exposure of 2 to 3 seconds, but very often exposures up to 30 seconds are used, depending greatly on the weight of the fabric, heavier fabrics normally requiring more heat. Extended exposures up to 10 or 30 minutes are only objectionable for their effect on mass production technique and very often such extended exposures are necessitated in the normal course of events, such as for splicing together webs of glass fibers in a unit of operation.

In the event that temperatures during weave setting are allowed to exceed that capable of fusing the fibers, the resultant anchoring of the fibers one to another at their junctures ultimately leads to the distintegration of the fiber. and corresponding weakening of the textile. fabric.

Most textile glass fibers are coated with a lubricant and binding agent, usually applied during the fabrication of the fibers into strands or yarns. One purpose of the size or coating is to protect the fibers against mutual abrasion while permitting the fibers to move relative to each other during fabric formation and flexure of the fabric. Such lubricant and binding agents are chiefly organic in character and upon exposure to the high temperatures of weave setting they are almost immediately burned or distilled from the fiber surfaces. To permit distillation or burning of the organic constituents cleanly from the fiber surfaces, that is without any tendency to discoloring the fibers by carbonization products, it is preferable to carry out weave setting in an oxidizing atmosphere; Suitable conditions are found to exist when the substances burn off with a bluish flame, whereas if they burn off with a yellowish flame, indicative of reducing conditions, carbonization may result and deposit discoloring substances on the fibers that arethereafter diflicult to remove. Suitable oxidizing conditions are secured by allowing access of air to the burning zone or by injection of oxygen or oxygenenriched gases into the chamber or oven employed for weave setting.

Heat curing may follow Weave setting at any time, but it is preferably carried out immediately thereafter in a continuous operation. Heat curing constitutes exposure of the fabric with an organo silicon compound on the surface of the fibers to a temperature in the range of 550 F.'to 850 F. or higher for a period of time ranging from one to thirty minutes, depending upon the weight of the fabric, the amount and type of organo silicon compound and the temperature for heat curing. Naturally, a thinner organo silicon film on the fibrous surfaces will require less time to effect the desired thermal reaction. Best practice dictates the use of about 600 F. to 750 F. for 3 to minutes, depending upon whether softness in varying degrees is desired in the final product, as will hereinafter be explained.

Suitable organo silicon compounds for reaction on the glass fiber surfaces during heat curing are selected from the materials of the type formed by the condensation polymerization of the hydrolysis products of organo silanes having the general formula R SiX where R is hydrogen or preferably a monovalent organic radical of the type aliphatic, alicyclic, aromatic, mixed aliphaticaromatic, and heterocyclic. Representative of suitable R groups are aliphatic groups of the type methyl, ethyl, propyl, isopropyl, 'butyl, amyl, hexyl, heptyl, octadecyl, and the like; alicyclic groups of the type cyclopentyl and cyclohexyl; aromatic and mixed aliphatic-aromatic groups of the type phenyl, mono-, and polyalkyl phenyls including tolyl, xylyl and mesityl, mono-, di-, and triethyl phenyls, naphthyls, di-ethyl naphthyls, tri-propyl naphthyls, tetra-hydro naphthyls, anthracyl, benzyl, phenyl ethyl and the like; and heterocyclic groups such as furfuryl. When aliphatic or mixed aliphatic-aromatic, the aliphatic group may be branched or straight chained and it may be saturated or unsaturated, as in allyl, methallyl, vinyl, styryl, and the like. The organic groups may be halogenated derivatives and when the organic group is sufficiently large to prevent hydrolysis, the R groups may constitute an alkoxy or aroxy group which attaches to the silicon atom through oxygen instead of through the usual attachment through the terminal carbon atom. X is a readily hydrolyzable group of the type consisting of a halogino, amino, alkoxy, aroxy, acyloxy and the like. n is either one, two or three.

Suitable polymers thus constitute a number of building units of the type but the building unit may also include polymers constituted with building units having a formula corresponding to such as described in the patent to Rochow No. 2,383,817. Eventually each polymeric molecule is terminated by a blocking unit which may constitute one of the R groups previously described, but before it is terminated, the length of the molecular chain may be varied to include a small number of building units to many thousand building units with the result that the organo silicon compound produced may vary from a liquid of low consistency through a heavy oil or wax to an elastomer or a resinous solid. When properly terminated the organo silicon is relatively stable to temperatures as high as 500 F. to 600 R, which temperature ordinarily constitutes the maximum recommended temperature for driving oh? the diluent and setting the organo silicon material in the application of the material as a treatment or coating.

The preferred organo silicon compounds are selected from the low molecular weight polymers, generally referred to as polysiloxane or silicone fluids, oils or parting compounds. These substances vary according to their molecular length and the organic R groups of which the building units are composed. For example, suitable oils, liquids, or compounds are dimethyl polysiloxane, and copolymers such as phenyl methyl, polysiloxane and the like. Higher viscosity substances and resinous materials are illustrated by the copolymers of phenylmethyl, phenyl ill '4 and methyl siloxanes, dimethyl and phenyl and methyl siloxanes, and elastomeric materials are characterized by the presence of slightly less than two organic R groups for each silicon atom to permit occasional cross linkages.

Although best results are secured by the use of a polymer, many of the purposes for an organo silicon coating are secured when the organo silicon polymer is wholly or partially replaced by an organo silane of the type which constitutes the monomer previously described. For example, use may be made of octadecyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, methyltriethoxysilane, dimethyldiethoxysilane, methyldichlorosilane, dimethylchlorosilane, phenylmethyldiethoxy silane, diphenyldiethoxysilane, diphenyldichlorosilane, and the like.

Organo silicon compounds .of the type described may be deposited from solvent solution in which aromatic naphtha or coal tar hydrocarbons, such as Stoddard solvent, constitute the major diluent, but it is more economical and safer, at these high temperatures, to rely upon the application of the organo silicon compounds from aqueous dispersion or emulsions. These may include a conventional dispersing or emulsifying agent for stabilization purposes. Application of the organo silicon to the glass fiber surfaces following weave setting may be made by conventional coating, or padder application. Alternatively, the fabric may be submerged in a bath of the treating composition, followed by a squeezing operation to enhance the distribution and to remove the excess. In the event that a silane constitutes the organo silicon compound, deposition of a desired character may be made by vapor deposition. Sufficient quantity of organo silicon compound may be deposited on the glass fiber surfaces from treating compositions having from 0.5 to 10.0 percent by weight organo silicon, but higher or lower solids content may be used, the aim being to have about 0.05 to 2.0 percent by weight of organo silicon on the finished fabric.

The lower limit of organo silicon which it is desired to deposit over the glass fiber surfaces is an amount sufficient to cover the fibers with at least a monomolecular film while the upper limit is an amount which will not unduly stiffen the fabric or tend to bind the fibers one to another.

Although the application of the organo silicon compound and subsequent heat treatment may be efiected at any time subsequent to weave setting, it is best to coat the fibers immediately after weave setting. This is because, in Weave setting, the fibers are reduced to a bone dry state and are free of any protective coating. Any relative movement of the fibers while they are in this condition causes microscopic scratches and fractures which have telling efiect upon the strength of the fibers and the fabrics formed therefrom. Another reason is that the moisture layer, usually present on the glass fiber surfaces, appears to be removed by the rigorous conditions of the weave setting. This leaves the surfaces of the fibers in condition capable of more complete integration with the organo silicon compound, which has a chemical composition favoring reaction with the groups that predominate on the dry glass fiber surfaces.

, When applied, the organo silicon compound functions in the dual capacity of a lubricant and a protective agent and is subsequently converted into a complex reaction product by the thermal reaction of heat curing, which treatment may follow at any time, but conveniently is carried out as a continuous operation immediately following the organo silicon coating.

It is difficult to point to any one concept responsible for the new characteristics secured in a fabric prepared according to this invention. Previously, glass fibers and fabrics formed therefrom have been heat treated at temperatures of 500 F. to 800 F., usually at about 650 R, to burn off the size or hinder. Any degree of weave setting or fiber relaxation resulting from these earlier ing off of the size.

processes did not give the characteristics securedby "this invention. In fact, the heat treatment of the prior art taught the opposite result because the feel, hand and strength of the heat treated fabric were poorer than in the original product.

There have also been some instances wherein glass fiber fabrics have been coated with organo silicon compounds applied to the fabrics from solutions or emulsions and then dried and heated for a short time to remove the diluent and set the organo silicon on the glass fiber surfaces. Yet, in none of these cases has there been any apparent improvement in the properties of the fabric with respect to feel, hand and draping qualities.

Glassfibers and fabrics formed therefrom have been treated with an organo silicon compound following burn- Yet none of the products secured therefrom have the characteristics which compare to those secured by products manufactured in accordance with this invention. Fibers and fabrics heretofore produced all suffered from brashiness and they were lacking in feel or hand of the type that is characteristic of the finer silk and wool fabrics. Glass fiber fabrics heretofore produced were relatively stiff and lifeless, they did not drape properly, but instead wrinkled and creased readily and if wall hangings, draperies and curtains were disturbed, they remained poised at odd angles.

There is reason to believe that the improved characteristics, new to glass fiber fabrics, flow primarily from a relaxation of the fibers, due to the weave setting coupled with the modification of the glass fiber surfaces by the organo silicon treatment. There is clear evidence of molecular relaxation from the tense orientated position taken by the molecules during fiber attenuation. This may be illustrated by the increase in density occasioned by the readjustment of the molecular arrangement to relaxed condition, as exemplified by the increase in specific gravity during heat treatment to a substantially constant value. For example, glass fibers having a density of about 2.54 grams per cc. increase in density by as much as 0.025 gram per cc. during weave setting with very little further increase possible thereafter.

There is further evidence of physical relaxation of fibers made tense by the various thread, yarn and fabric forming steps wherein the glass fibers are twisted together and plied and then looped back and forth over crossing yarns in standard weaving and knitting operations. During heat treatment the fibers appear to assume their existing undulated, curly or twisted forms as their natural state, that is, they become weave set. Thus they may thereafter be freely flexed in any direction without aggrar vation of fiber tcnseness and there is a tendency for the fibers thereafter to return to their set position. The automatic return characteristics tend to give life, crease and wrinkle resistance to the fabric. Even when a fiber is broken, the fracture will be substantially concealed because the free ends will lie in their acquired position instead of projecting from the fabric or yarn as pointed rods, as in fabrics heretofore produced.

Most of the fiber relaxation and weave setting occurs in the early part of the Weave setting operation and therefore it is incumbent to take precautions to align the fibers and the fabric properly as they pass through the weave setting oven, otherwise the wrinkles or other temporary irregularities will become a permanent part of ,the fabric. Coupled with-this feature are the unusual and novel designs made possible by pressing the fabric over rolls or between cooperating forms having certain designs in relief in one form and intaglio in the other. Thedesign thus becomes a permanent part of the relaxed fabric coming from the weave setting operations.

The unusual characteristics in glass fibers and fabrics formed therefrom may result from a new relationship established between the glass fibers and the organo silicon sible absence of a moisture barrier between the glass fiber surfaces and the organo silicon applied almost immediately after weave setting suggests possible reaction with the formation of a new reaction product modifying the surface characteristics of glass fibers. In the absence of the moisture layer, the glass fiber surfaces may be more completely wet-out by the organo silicon to provide a pro tective coating which fully covers all of the glass fiber surfaces to impart the protection and frictional or antislip characteristics desired of a coating material The time and temperature conditions for heat curing with an organo silicon coating suggests that the treatment of .the organo silicon goes beyond that theretofore used for driving off the diluent and setting the compound. Reformation of the organo silicon molecule or reaction thereof with the glass fiber surfaces is evidenced by the increased stiffness or crispness in the final product resulting from continued heat treatment. Such increased crispness could result from further polymerization of the coating to harder derivatives or higher molecular weight organo silicons. It might logically be caused by the removal of organic groups leaving the harder forms of silicon derivatives which may eventually unite with the glass surface to form an integral part of the glass fibers. This or some other phenomenon makes it possible, through heat treatment, to vary the properties of the final product from a fabric of silky softness to a fabric of starchy crispness. The heat treated organo silicon appears to form on the fibers protective sleeves of selected hardness which influence the cifect of weave setting and gives slip of a desired character between fibers even when present in what apparently is a substantially monomolecular layer.

This process and product is not limited to any particular type of glass fibers but is applicable to fabrics of continuous type glass fibers and to fabrics of staple type fibers and combination thereof, and to fabrics of any of the different types of glass fibers in combination with other fibrous materials for example, asbestos, capable of withstanding the processing conditions.

When the organo silicon compound is applied as an emulsion, it is desirable to formulate the treating composition with a small amount of emulsifying agent, such as a soap formed by the reaction of oleic acid or other fatty acid with morpholine or other soap forming amines, or metal bases to form the common metallic soaps. Many other conventional wetting agents and emulsifying agents may be similarly employed, such for example, as sodium lauryl sulphonate, dioctyl esters of sodium sulfosuccinate, triethanolamine, sulfonated ethers, quaternary ammonium salts and the like. It is sufficient if the wetting agent or emulsifying agent comprises to 5 percent of the treatingcomposition although no more than 2 percent is usually used.

It has been found that fabrics prepared in accordance with this invention may be substantially permanently colored by after treatment with a coloring medium which may be coated and impregnated with any of the conventional synthetic resins to make coated fabrics, reinforced plastic bodies, and plastic laminates. To produce coated fabrics the cloth of the invention may be run through a conventional coating machine'and have a continuous, void-free coating of vinyl acetate-vinyl chloride copolycompounddaringhcat setting.v For one-.tbing, the posjo ner, polyvinyl .butyral, polyvinylchloride, polymethyb 7 methacrylate, butadiene-acrylonitrile copolymer, butadienestyrene copolymer, polystyrene, phenol-formaldehyde, polyesters, polyamides, or other conventional coating resin with or without plasticizer applied thereto. In making plastic laminates, the cloth of the present invention is impregnated with one of the conventional laminating resins and the impregnated cloth is arranged in superposed layers to the desired thickness and the superposed layers subjected to pressure and heat to compact the laminate and cure the resin.

For the purpose of illustration, but not of limitation, processes for carrying out the invention are shown schematically in the accompanying drawing, in which:

Figure l is a schematic diagram of the elements for carrying out this invention by a continuous process;

Figure 2 is a partial operating diagram showing a modification in the step of applying the organo silicon;

Figure 3 illustrates a further modification of the apparatus outlined in Figure 1;

Figure 4 is a transverse vertical sectional view through a modified weave setting furnace;

Figure 5 is a vertical longitudinal sectional view through a different type of weave setting furnace; and

Figure 6 is a similar view through a vertically extending weave setting furnace.

As shown in the drawing, a web 10 of a glass fiber fabric which may be a textile woven or knitted of continuous type or staple type fibers having a lubricant and binder on the surfaces thereof, is fed from a cloth unwinder 11. The web it) is advanced through suitable conventional cloth tensioning, straightening and guiding elements 13 to eliminate wrinkles and folds, and to provide uniform tension and align the cloth before it enters the horizontal weave set oven 14-.

The weave set oven is maintained at a temperature of about 1200 F. and is of a length to permit exposure of the web to these temperatures for about 3 to 15 seconds. it will be observed that at this temperature and a speed selected to result in such an exposure, the organic material on the glass fiber surfaces burns from the fabric shortly after it enters the weave setting oven. At such speed and temperature the flame of the burning organic material extends across the web of fabric as a narrow band located within the first half of the oven measured in the direction of movement of the fabric and probably within a few inches of the entrance opening to the oven 14. It is important, as previously pointed out, that the organic materials distill cleanly from the glass fiber surfaces and burn under oxidizing conditions Without carbonization.

By providing openings 15 and 16 at the inlet and the outlet larger than that required for the passage of the web, air is admitted in the desired quantity for maintaining oxidizing conditions. The oven may be heated by electrical coils, radiant gas burners or in other suitable manner. It is desirable to maintain temperature distribution of equal character throughout the oven i. e., both above and below the fabric in order that the rate of burning-off and weave setting will be substantially uniform across the web, thereby to insure uniform stress distribution and weave setting.

This results in the band of flame being substantially constant in width and extending perpendicular to the direction of travel of the fabric.

The heating means may be located above, below, or both above and below, the fabric and probably should radiate heat from both sides to the fabric. One arrangement is shown in Figure 1. The oven 14 is designed to radiate heat to both sides of the fabric by emissivity from ceramic or refractory walls which serve as radiant heating elements and which are heated to heat radiating temperature by heat applied to the oven from heating ducts 17.

A difierent construction also capable of maintaining uniform oven temperature is illustrated in Figure 4 where a mufile furnace 43 is shown. The furnace 43 has a mufile 44 formed by top and bottom plates 45 and 46, side plates 47 and end plates 48. The end plates 48 are designed to provide large entrance and exit openings, such as the exit opening 49 shown in Figure 4. The furnace interior, exteriorly of the muflle 44, is heated by gas burners 50. This heats the atmosphere within the furnace 43 around the muffle 44 and raises the temperature of the plates 45, 46 and 47 so that they radiate heat, in turn, to the length of cloth 51 being fed through the furnace 43. Gases from the burning organic size material on the cloth 51 are carried away through a muffle flue 52 and the products of combustion of the heating gases burned in the furnace pass around the muli'le 44 and out a combination flue 53.

Another arrangement using radiant electric heating coils is shown in Figure 5. In this construction a. furnace 54 is constructed of insulating material and has two sets of radiant electric heating coils 55 and 56 located above and below the plane of movement of the cloth to be treated, the cloth being indicated at 57. As in the earlier described arrangements, the temperature of the oven 54 is maintained at such a level and the fabric 57 is moved longitudinally therethrough at such speed that the organic size material on the fabric' 57 burns off shortly after the fabric 57 enters the weave setting oven 54, as shown by the legend flame band. The gases from the burning organic size material are carried out of the oven through a fiue 58. If instead of a horizontal oven, a vertical oven is used, less stress is placed upon the fabric as it advances through the weave setting operation with consequent advantages. In a vertical oven the cloth may move either upwardly or downwardly with the exit at the top or bottom, respectively. Figure 6 shows a weave setting oven 59. Cloth 60 is led from a tensioning device (not shown) around a guide roll 61 and upwardly through the oven 59. The cloth 60 then passes over guide rolls 62 and downwardly to padders and other textile equipment (not shown) for subsequent treatment. In this construction, a plurality of radiant gas burners 63 is shown on both sides of the cloth 60 for heating the organic size to ignition temperature. As in the earlier described embodiments of weave set furnaces for practicing the invention, the organic size material on the fabric or cloth 60 reaches ignition temperature and burns away in a narrow band of flame extending transversely across the cloth 60 near an entrance opening 64 of the oven 59.

From the weave setting oven 14, the web 10 is immediately passed over idler roller 18 and into an impregnation tank 19 filled with the organo silicon treating composition 20. The coated fibers are then advanced between squeeze rolls of a padder 21 for effecting uniform distribution of the organo silicon treating composition and the removing of excesses from the fabric.

A suitable formulation for treating the glass fibers following weave setting will include a 2 percent solution of dimethyl polysiloxane (500 centistokes viscosity) dissolved in Stoddard solvent. Instead of dimethyl polysiloxane any one or more of the previously described organo silicon compounds may be used and the concentration therein may range from 0.5 to 10 or more percent by weight. When it is desired to treat the fibers with an organo silicon arranged in aqueous dispersion the following composition may be used:

In this latter formulation the water should be heated to about 170 F. before the morpholine is added. Then Part 1 is slowly added with agitation to Part 2 to form a stable emulsion which may be poured into the dip tank 19. It will be manifest that other emulsifying agents of the type previously described may be used instead of the morpholine soap.

From the padder 21, the coated web 22 enters the curing oven 23, maintained at a temperature selected between 600 to 750 F. wherein the diluent is removed and the organo silicon is reacted to a degree of cure calculated to give the fabric the desired hand and crispness. To provide for extended exposure in the curing oven 23, idler rollers 24 may be arranged therein for directing the web back and forth as it travels through the oven.

It is desirable to maintain temperature uniformity across the fabric in the curing oven, in order to provide uniformity in the characteristics of the final product. Since resinous cure seems to provide some of the characteristics in the fabric, it is desirable that the fabric pass through the oven in such a manner that non-uniform conditions which might form wrinkles or ripples will be eliminated.

After passing through the curing oven the fabric is cooled to room temperature by exposure to the atmosphere, but it may be cooled by passing it about water cooled rolls 25, before it is collected as a final product 26, upon cloth wind-up roll 27, that is designed to impart a constant lineal speed and uniform tension to the cloth as it travels through the apparatus.

In order to minimize mutual abrasion between fibers While they are in their bone-dry or unprotected condition following weave setting, it is best to apply the organo silicon as quickly as possible and with a minimum amount of flexing of the fabric in the interim. To this end, the fabric travels in a plane through the weave set oven, and in the modification shown in Figure 2, silicone treatment is effected while the weave set fabric travels in a straight line from the weave set oven M. For this purpose, spray guns 30 are employed to deposit the proper amount of organo silicon treating composition on the glass fiber surfaces, which amount may range from 0.5 to 10 percent by weight of the compositions, or 0.05 to 2 percent by weight organo silicon solids of the type previously described. Usually the amount deposited by the spray guns is sufiicient to wet the fibers ofthe fabric, which is then advanced between squeeze rolls 31 to enhance distribution and to remove excess of the organo silicon composition. Excess which is removed falls into a drip pan 32 along with drippings from the spray application.

Figure 3 shows another straight line operation wherein an organo silicon compound coating is applied to the fiber surfaces by vapor deposition. For this purpose a bath 40 of organo silane of the type previously described, such as dimethyl dichlorosilane, tetraphenylsilane, methyl trichlorosilane and the like, is heated by burners 41 in an enclosed melting pot 42 to the temperature at which vapors are released which deposit upon the class fibers of the fabric .12 as it travels in close vicinity to the vaporizing fluids.

When it is desired to color the fabrics, a composition corresponding to the following may be applied by conventional printing or coloring methods:

25 parts butadiene-acrylonitrile copolymer (I-Iycar-OR) 80 parts water 4 parts oleic acid 4 parts morpholine 6 parts organic dye or coloring pigment In this type of formulation, the oleic acid and morpholine react to form a wetting agent which may be replaced in the formulation by other well known wetting agents such as cationic-active amines having more than 10 carbon atoms, quarternary ammonium salts, organo silicon fluids '10 and compounds and the like. The amount of coloring agent may be varied from 6 percent to give the desired efiect. Other adherent coating or resinous materials, such as the vinyl polymers and copolymers, urea-aldehyde resins, polyacrylic acid derivatives, natural resins and rubber-like substances, and the like, may be used as the base for the coloring matter.

To produce loose curly glass fibers that can be carded and spun like wool, a fabric woven or knitted of staple type fibers, following weave setting or following application of the organo silicon and its curing, may be passed through a battery of cutters, choppers, pickers and like machines to tear the fabric apart and separate the fibers to substantial extent, the separated fibers having the curls and undulations set into them by the weave setting. Alternatively a fabric of interwoven or inter knitted continuous type glass fibers may similarly be treated although in such a case the operations should include the step of chopping or cutting the fabric into pieces one or two inches across their greatest dimension to thereby provide the soft fibers usually desired.

By the practice of the present invention, it is possible to provide glass fiber fabrics which, for given fiber diameters, are exceptionally soft and supple. These properties, new to glass fabrics, make the fabrics drape easily into soft folds and pleats and give most of the desirable characteristics of the finest silks. treated glass fibers lie stiff and wrinkled whereas fabrics treated according to this invention refuse to be creased or crumpled and exhibit very attractive life-like properties.

The invention has been described in connection with all-glass fabrics, but it is equally useful in the treatment of textile products made of glass and asbestos yarns, such as the yarns and fabrics disclosed in the Simpson Patent 2,132,702.

It will be understood that numerous changes in methods of treatment, conditions and formulations may be made without departing from the invention, especially as defined in the following claims.

I claim:

1. A process for burning an organic size from a glass fabric comprising interlaced yarns formed of glass filaments, which process includes the steps of: continuously and progressively moving said glass fabric through a zone containing an atmosphere having an excess of oxygen over and above that required for complete combustion of said organic size; heating said atmosphere and the glass fabric moving therethrough by applying heat to said atmosphere and to said fabric while in said zone to heat said fabric progressively until combustion of said organic size takes place, said combustion forming a surface flame in a band transverse to the direction of movement of said glass fabric, said combustion tending to deplete the oxygen in said atmosphere; maintaining the speed of said fabric at a value to retain the surfaceflame band in a substantially fixed position in said zone; and continuously renewing the oxygen content of. said atmosphere in said zone.

2. A process for burning an organic size from a glass fabric comprising interlaced yarns formed of glass filaments, which process includes the steps of: continuously and smoothly moving said glass fabric through a zone containing an atmosphere having an excess of oxygen over and above that amount of oxygen required for complete combustion of said organic size; heating said atmosphere and the glass fabric moving therethrough to heat said fabric progressively until volatile products are released from said size to ignite and burn as a surface flame in a band transverse to the direction of movement of said fabric through said zone, said surface flame being immediately adjacent said fabric; and maintaining the speed of said fabric at a value to retain the surfaceflame band in a substantially fixed position in said zone.

3. A process as defined in claim 2, in which the speed By comparison, 1111-- 11 of said fabric is maintained to retain the surface-flame band at a position substantially within the first half of the length of said zone measured parallel to the direction of movement of said fabric therethrough.

4. A process as defined in claim 2, in which said atmosphere and said glass fabric are heated by radiating heat to said fabric from both sides of said zone and toward the opposed faces of the fabric moving therethrough.

5. A process as defined in claim 2 involving the use of heating elements on opposite sides of said zone and spaced from each other a distance substantially greater than the thickness of said glass fabric to bound said zone, and in which said heating step is performed by heating said elements to a.heat-radiating temperature to radiate heat to the opposed faces of the moving glass fabric.

6. A process as defined in claim 2, in which said zone is an upright elongated zone having entrance and exit openings at its opposed ends, and including the step of guiding said fabric to move longitudinally through said zone while in a substantially planar configuration.

7. A process as defined in claim 6, in which said entrance and exit openings are respectively adjacent the lower and upper ends of said elongated zone and including the step of moving said glass fabric upwardly through said entrance opening, thence longitudinally through said zone and thence from said exit opening.

8. A process for the continuous heat treatment of a glass fabric comprising interlaced yarns formed of glass filaments coated with an organic size, said process including the steps of: continuously and progressively moving said fabric through an upright zone communicating with the atmosphere at its upper and lower ends by moving said glass fabric into one of said ends at a given rate while drawing said glass fabric from the other of said ends at exactly the same rate and maintaining the fabric in the zone under light tension, said zone containing an air atmosphere through which the fabric moves; applying heat to said atmosphere and to the fabric moving therethrough to bring said fabric to a size-burning temperature to burn the size from the fabric, the small tension on said fabric being insufficient to cause elongation thereof while at elevated temperature in said upright zone; maintain- 12 ing the speed of the glass fabric at a value to maintain the zone of burning at a substantially fixed position in said upright zone; and cooling sL-id glass fabric upon withdrawal from said zone.

9. A continuous process for the heat treating of a glass fabric comprising interlaced yarns formed of glass filaments coated with an organic size to remove said size and set said yarns in the configuration in which they are present in the fabric, said process including the steps of: continuously moving said fabric through an elongated heating zone; applying heat to said fabric throughout the elongated heating zone while said fabric is in contact with an air atmosphere in said zone; and controlling the speed of said fabric to maintain any section thereof in said zone for a sufficient time to eflfect said setting of said yarns, the temperature in a portion of said zone being sufficient to effect autoignition of said size, the temperature in said zone being between about 1100 F. and 1400 F.

10. A continuous process for the treatment of glass fabrics comprising interlaced yarns formed of glass filaments coated with an organic size, said process including the steps of: continuously and sequentially moving the glass fabric through a heating zone, a cooling zone and a finishing zone; applying heat to said glass fabric in said heating zone to bring same to a size-burning temperature to burn said organic size from said fabric, the speed of the glass fabric being such as to maintain the zone of burning at a substantially fixed position in said heating zone, the heated fabric being cooled in said cooling zone, said cooling being sutficient only to cool the fabric to a temperature substantially above room temperature; applying a coating of a liquid silicone to said .ass fabric during its continuous passage through said ishing zone, said coating being applied while said fabric at such temperature substantially above room temperature and thus minimizing the amount of water tending to adsorb on the glass fabric before application of said silicone coating; and continuously drying the silicone coating on the fabric by heating the fabric to a temperature or about 450-700 F.

No references cited. 

6. A PROCESS AS DEFINED IN CLAIM 2, IN WHICH SAID ZONE IS AN UPRIGHT ELONGATED ZONE HAVING ENTRANCE AND EXIT OPENINGS AT ITS OPPOSED ENDS, AND INCLUDING THE STEP OF 